Anatomically conforming vaginal insert

ABSTRACT

A vaginal insert formed from a composition that, prior to introduction to the vagina, has the physical properties of a liquid, semi-soft gel, paste, foam, or viscous material so that it can be effectively delivered to the vaginal canal. After introduction into the vagina, the composition will expand and/or solidify into a semi-solid or solid structure to substantially fill the entire “H” shaped space of the vagina and a portion of the rugal folds along the length of the vaginal canal. Upon solidifying, the composition defines an insert that, in one embodiment, is suitable for use as a tampon and, in another embodiment, is suitable for use as an incontinence device.

BACKGROUND OF THE INVENTION

The present invention relates to a composition, device, and a method ofdelivery for an anatomically conforming vaginal insert.

There have been numerous devices developed to address issues of urinaryincontinence and menstruation. Many of these devices are generallyround, rectangular, or ovoid in shape. However, the vagina is a hollowfibro-muscular, non-cylindrical tube in which the right and left lateralwalls form what resembles an “H” shape with the anterior and posteriorwalls collapsed upon each other. Additionally, the surface of the vaginais not smooth, there are small ridges on the inner surface of the vaginathat extend laterally and upward from the columna rugarum (the longridges on the anterior and posterior walls). Therefore, while the abovedevices are successful, it is believed that they could be improved tobetter take into consideration the shape and internal structures of thevagina.

The present invention addresses that need.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, therefore, an anatomicallyconforming vaginal insert is provided. The insert is desirablyflushable, discardable, or biodegradable and is also biocompatible andsuitable for placement in the human body. The insert is a compositionthat, prior to introduction into the vagina, has the physical propertiesof a liquid, semi-soft liquid, gel, paste, foam, or viscous material sothat it can be easily and effectively delivered into the vaginal canal.After the material has been introduced into the vaginal canal, thecomposition will expand into a portion of the rugal folds and makeintimate contact with a portion the rugae where the consistency of thematerial will increase in solidity, forming a semi-solid or solidstructure to substantially fill the entire “H” shaped space of thevagina within a portion of the vaginal canal. The intimate contact withthe rugae ensures that the device will be securely held in place andadditionally will not allow the passage of bodily fluids from the uterusor the urethra. Upon solidifying, the composition defines an insertthat, in one embodiment, is suitable for use as a tampon and, in anotherembodiment, is suitable for use as a continence restoration device.

The composition can be delivered to the vagina by any suitable methodincluding an aerosol, squeeze tube, pump or other applicators (known inthe art) to which a nozzle is attached or a part of the container.Additionally a suppository, capsule, effervescent or foam producingtablet could also be used to deliver the material into the vaginalcanal.

As noted above, in one embodiment, the insert can be used as acontinence restoring device, to provide physical support to the bladderneck region by restoring it to normal anatomical position. Because thedevice substantially fills the entire “H” shaped space of the vaginawithin a significant portion of the vaginal canal, the device will alsoact as a backdrop to support the weakened musculature around the bladderneck and urethra to prevent or substantially reduce leakage. Inaddition, the insert will close off the urethra when increased abdominalpressure occurs, for example, upon coughing, laughing, exercising,lifting, or sneezing but does not interfere with the voluntary releaseof urine (micturation).

In this embodiment, the composition is non-absorbent and desirablyhydrophobic. The composition includes a material selected frompolyurethane, silicone, temperature sensitive polymeric materials, ionsensitive polymeric materials, humidity activated materials having ashape memory.

In another embodiment, the insert is contemplated as a catamenialdevice. In this embodiment, the insert attracts and/or holds menstrualfluids. The composition forming the insert can be hydrophilic so long asthe insert can attract and/or hold the menstrual fluid within theinterstitial spaces of the material and prevent leaks.

In this embodiment, the composition includes open-cell polyurethanefoams, a multi-component reverse thermo-sensitive polymeric system suchas that shown and described in PCT publication WO 03/017972, thecontents of which are incorporated by reference, a fibrous absorbentstructure resembling an open cell polymeric foam such as that shown anddescribed in U.S. Pat. No. 6,261,679 the contents of which areincorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a mid-sagittal section of a human torso showing one embodimentof the material of the present invention deposited in the vaginal canaland acting as an incontinence device. The material fills the entirevaginal cavity and numerous rugae allowing restoration to nearly normalanatomical position furthermore, by cooperating with the symphysis pubisto allow the urethral tube to be compressed upon itself and alleviateurinary incontinence during episodes of increased intra-abdominalpressure.

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 with thematerial of the present invention not present within the vaginal cavity.

FIG. 3 is the same sectional view of FIG. 2, except that the material ofthe present invention is present within a portion of the vaginal cavity.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to FIG. 1, a human torso 10 of a female is shown with avagina 12, a cervix 14, a uterus 16, a urethra 18, a bladder 20 and asymphysis pubis 22. The vagina 12 has an introital opening 24 that exitsthe human body 10 that contains a vaginal canal 26 that extends from theintroital opening 24 to the cervix 14. The vaginal canal 26 has a lengththat ranges from between about 4 inches to about 6 inches (about 102millimeters (mm), to about 153 mm) in most women. The cervix 14 is theentrance to the womb and is located between the upper aspect of thevaginal canal 26 and the uterus 16. The rectum 27 is located posteriorto the vagina 12. The vaginal canal 26 has an inner periphery 28.

As best seen in FIGS. 2 and 3, the inner periphery 28 is made up of aright lateral wall 30, a left lateral wall 32, an anterior wall 34, anda posterior wall 36. The four walls 30, 32, 34, and 36 generally definean H-shape and encompass the entire 360 degrees of the inner periphery28. The inner periphery consists of rugal folds 39. The anterior wall 34is located closest to the urethra 18 and the urethra 18 is locatedbetween the symphysis pubis 22 and the vagina 12.

The vaginal canal 26 can be divided into three approximately equalsections, each representing about one-third of the overall length. Eachsection is approximately 2 inches (approximately 51 mm) in length. Themiddle third of the vaginal canal 26 is typically the most importantsection for alleviating female urinary incontinence because of itsproximity to the urethra 18. However, in the invention, the materialfills the entire length of the vagina and a penetrates into a portion ofthe rugal folds along its length making positioning in the middle thirdunimportant. The middle third of the vaginal canal 26 is alsohorizontally offset from the symphysis pubis 22, which is a bonyprominence situated adjacent to a front portion 38 of the human torso10. Cooperation between a urinary incontinence device positioned alongthe length of the vagina 12 and the symphysis pubis 22 further allowsthe urethra 18 to be compressed upon itself to alleviate involuntaryurine flow from the bladder.

The urethra 18, also referred to as the urethral tube, is a hollow,tubular structure that extends from a first opening (urethral meatus) 40that exits the human body 10 to a second opening 42 situated at thelower surface of the bladder 20. The urethra 18 has a length of about1.5 inches (about 38 mm) in most women. The urethra functions todischarge urine, which is temporarily stored in the bladder 20, from thehuman body. The urethra 18 has a plurality of urethral sphincter muscles44 located along the length of its inner periphery. The urethralsphincter muscles 44 are situated below the opening 42 and are ring likemuscles that normally maintain constriction of the urethra 18 to preventthe passage of urine. The relaxation of the urethral sphincter muscles44 by normal physiological functioning will permit urine to bevoluntarily expelled from the body.

Again, referring to FIG. 1, the human torso 10 further includesmusculature and body tissue located in the urethrovaginal myofascialarea 46 that is situated between the vagina 12 and the symphysis pubis22. The bladder 20 lies posterior to the symphysis pubis 22 and isseparated from the rectum 27 by the vagina 12 and the uterus 16. Theureters (not shown) that transport urine from the kidneys to the bladder20, pass from the pelvis to the posterior aspect of the urinary bladder20. The fundus vesicae 48, into which both of the ureters terminate islocated adjacent to the anterior wall 34 of the vagina 12.

As shown in FIG. 1, according to one embodiment of the presentinvention, the composition of the present invention is shown depositedwithin the vagina 12 and in the form of a urinary incontinence device100 positioned in the vaginal canal 26. The urinary incontinence device100 is designed to bridge across and along the length of the vagina 12to support the musculature and body tissue located in theurethra-vaginal myofascial area 46. It will be understood from thefollowing description that the incontinence device will substantiallyfill the entire lateral 360 degree originally H-shaped space of thevagina 12 along the entire length of the vaginal canal 26.

FIG. 3 shows the device, by virtue of its placement and composition,acting as an incontinence device 100. It will be noted that the devicesubstantially fills the entire space of the vagina 12 providing asupportive backdrop for the urethral tube 18. The urethral tube 18 cannow be sufficiently compressed during increased intra-abdominal pressureperiods thereby intercepting the flow of urine and also to providesupport to the urinary sphincter muscle 44 so that it can functionproperly. By permitting the urethral tube 18 to be compressed uponitself between the urinary incontinence device 100 and the symphysispubis 22, the involuntary flow of urine from the bladder is limited.

As noted above, the composition of the present invention can be chosento provide a urinary incontinence insert or to provide a catamenialinsert. The composition desirably is a low surface tension material thatwill allow uniform expansion under relatively low pressure. As a result,the composition will expand then solidify when present in the vaginalcanal and will conform to the shape of the vagina, penetrating a portionof the folds of the mucous membrane (ruga) of the walls 30, 32, 34, and36. The composition will substantially or effectively seal a portion ofthe vaginal canal. In this regard, the composition includes a materialselected from polyurethane, silicone, a hydrogel, temperature sensitivepolymeric materials, ion sensitive materials, bioelastic polypeptidepolymers, a multi-component reverse thermo-sensitive polymeric systemsuch as that shown and described in PCT publication WO 03/017972, thecontents of which are incorporated by reference, a fibrous absorbentstructure resembling an open cell polymeric foam such as that shown anddescribed in U.S. Pat. No. 6,261,679 the contents of which areincorporated herein by reference.

The polyurethane material may be an elastomeric or foam material thancan be prepared using a relatively low amount of water. A possiblepolyurethane material is described in U.S. Pat. No. 5,164,421, thecontents of which are incorporated herein by reference.

A silicon composition may include a medical grade silicone elastomer. Inthis embodiment, the uncured silicone elastomer in a fluid state isblended with a catalyst for solidifying the elastomer and a dilutionfluid to control the viscosity during delivery and to control themodulus of elasticity of the cured solidified material. The siliconeelastomer is self-curing and, upon curing has a modulus of elasticitythat is substantially the same as the vagina so that the insert, uponsolidifying remains resilient, can act as a physical support yet notcause discomfort.

The silicone may also include an organosilicon rubber, desirably afoamable polymer where the foam comprises a resilient, semi-rigid,closed-cell foam.

The composition of the present invention may also include a hydrogel.The term “hydrogel” as used in the specification refers towater-containing gels. These materials, when contacted with a bodyfluid, such as physiological fluids, swell at least 20% in volume. Theamount of swelling of the hydrogel material in contact with the bodyfluid is desirably preferably at least 40%, more desirably at least 80%and may well be in the range between 20 and 300% depending on thematerial used, amount of fluid to which the device is exposed and thelike.

The material should be essentially inert and harmless to the body fluidand surrounding tissues and should remain intact, that is, should not beabsorbed by the human or animal body into which the device is inserted.The material in the dry state should be essentially elastic and plasticonly to a very small extent. In its unswollen or non-hydrated state itmay be rigid, semi-rigid, or stiff, but should preferably soften uponswelling and retain a resilient property.

Suitable hydrogels are polymers and copolymers of the acrylic type suchas cross-linked polyacrylamide and polymers and copolymers of acrylicand methacrylic esters having at least one hydroxy radical in the sidechain. A preferred monomer is 2-hydroxy-ethyl-methacrylate; otherpreferred monomers are monometharylic esters of di- or triethyleneglycol of 2,3-dihydroxypropane. As cross-linking agents, polyfunctionalacrylates, such as the esters of the same glycols, e.g. ethyleneglycol-bis-methacrylate, are useful. Materials useful in accordance withthe present invention as well as a process for their preparation aredescribed in the U.S. Pat. No. 3,943,045, the disclosure of which ishereby incorporated by reference.

For example, a polymer of vinyl pyrrolidone and nylon in which liquidnylon or bulk nylon is polymerized with vinyl pyrrolidone, the nature ofthe reaction possibly being a graft polymerization or polymerizationfollowed by cross-linking. The resulting material may be termed ahydrogel. Using such a material, the swelling and the water absorptionpower may be altered by changing the amounts of nylon and vinylpyrrolidone to be polymerized. As an example, three (3) parts vinylpyrrolidone and 1 part nylon forms a polymer having an expansion factorof 1.48, that is, it swells 48% in water, with a water content of 66%;five (5) parts vinyl pyrrolidone and 1 part nylon forms a polymer havingan expansion factor of 1.78 with a water content of 78%. Othervariations in monomer proportions will produce corresponding changes inthe properties of the resulting hydrogel and are easily determined bythe skilled worker.

As noted above, the composition may include a temperature sensitivepolymeric material. Temperature sensitive polymeric materials aredescribed in PCT WO 98/29501, the entire contents of which areincorporated herein by reference.

The temperature sensitive polymeric materials may be based on modifiedhydroxypropylcellulose compositions. In particular, it is believed thatmethylated hydroxypropylcellulose (mHPC) compositions (notmethylhydroxypropylcellulose (MHPC), a copolymer of methylcellulose andhydroxypropylcellulose) will be effective for use as the insert of thepresent invention. These materials are described in U.S. Pat. No.5,770,528, the entire contents of which are incorporated herein byreference. It is noted that these materials may also be considered anion sensitive material.

m-HPC is produced by methylation of HPC with methylating agents such asdimethylsulfate or methylchloride. The cloud point of m-HPC can beprecisely controlled by the degree of methylation. Unlike HPC which,when precipitated in water, forms a supramolecular helical structurealong the backbone leading to a very loose, open precipitate with nogel-like property, m-HPC precipitates as a solid mass with a very lowlevel of hydration. This precipitation behavior may be caused by theintroduction of methyl groups, which disrupts the helical structure andincreases overall hydrophobicity of the polymer chain. m-HPC hascohesive energy and gel strength comparable topoly(N-isopropylacrylamide) (IPAM), above the triggering point. As usedherein the phrase “triggering point” or “trigger temperature” refers tothe LCST or cloud point temperature.

LCST polymers are Low Critical Solution Temperature polymers. A LCSTpolymer has the property of being less soluble at increased temperaturesthan at lower temperatures. The polymer has a lower critical solutiontemperature at which significant insolubilization occurs. A LCST polymermay have having a single LCST point. In some circumstances, however, itis appropriate to use a polymer solution which provides two differentLCST points, either as a result of including two LCST polymers havingdifferent LCST points or as a result of using a polymer having twodifferent LCST points. It will be appreciated that when the polymer orpolymer blend provides more than one LCST point there may be twodifferent zones at which insolubilization and/or solubilization occursor there may be a wide range of conditions at which these effects occur.

LCST polymers and their solution properties are well known and aredescribed in, for instance, Priest et al Chapter 18 in “Reversiblepolymeric gels and related systems”, American Chemical Society, 1987 andin U.S. Pat. Nos. 3,244,640, 3,567,650 and 3,594,326, WO92/20771 andJPB-92034983 and JP-B-92034985, JP-A-04139206 and in Galaev andMattiasson, Enzyme Microb. Technol., 1993, 15, 354-366. Suitablemonomers and polymerization techniques are described in U.S. Pat. No.5,147,923.

The LCST polymer may be a naturally occurring polymer such as certaincellulose derivatives, such as the methyl, hydroxypropyl and mixedmethyl/hydroxypropyl cellulose ethers. It is generally preferred thatthe LCST polymer to be a synthetic polymer formed by polymerization ofwhat can be termed an LCST monomer (or more than one such monomer),optionally as a copolymer with one or more further types of monomer.Suitable LCST monomers include N-alkylacrylamide, N,N-dialkylacrylamide,diacetone acrylamide, N-acryloylpyrrolidine, vinylacetate, certain(meth) acrylate esters (especially hydroxypropyl esters), styrene, andvarious other vinyl monomers, especially N-vinylimidazoline and thelike.

When the LCST polymer is a copolymer with other monomers, the co-monomeris usually hydrophilic and can be non-ionic or ionic. Suitable non-ionicmonomers include acrylamide (ACM), substituted acrylamides for instancethose with one or two aliphatic N-substituents, some of which, such asN,N-dimethyl acrylamide (NNDMACM), may contribute to LCST properties,hydroxyethyl acrylate, vinylpyrrolidine and hydrolysed vinyl acetate.Anionic or cationic monomer can be used in place of or in addition tothe non-ionic co-monomer to form a copolymer or terpolymer respectivelywith the one or more LCST monomers. Suitable anionic monomers includeethylenically unsaturated carboxylic or sulphonic acid monomers, forexample(meth)acrylic acid and alkaline salts thereof, and 2-acrylamidomethyl propane sulphonic acid. Suitable cationic monomers includedialkyl amino alkyl(meth)acrylates and acrylamides as acid additionproducts of quaternary ammonium salts, for exampledialkylaminoethyl(meth)acrylate acid addition salts.

Diacetone acrylamide (DMM), N,N-dimethyl acrylamide (NNDMACM),N-isopropyl acrylamide (NIPA) and N-hydroxypropyl acrylamide areparticularly useful LCST monomers. LCST polymers that may be usedinclude DAAM/ACM copolymers, NNDMACM/NIPA copolymers, NNDMACM/ACMcopolymers, NIPA/ACM copolymers and poly-N-isopropylacrylamide(poly-NIPA) homopolymer.

Ion sensitive polymers are described in U.S. Pat. No. 6,602,955, thecontents of which are incorporated herein by reference.

It is noted above that bioelastic polymers may be useful as thecomposition of the present invention. Bioelastic polymers are describedin U.S. Pat. No. 5,520,672, the contents of which are incorporatedherein by reference. The bioelastic polymers are capable from changingfrom a condensed to a swollen state upon contact with a pre-selectedphysiological condition (such as temperature or salt content) so thatthe inverse temperature transition point of the bioelastomer isselectively located either above or below the ambient temperature of thelocal environment in which the bioelastomer is found; this allowsselective unfolding and disassembly of polymer matrices to favorabsorbency or brings about a contraction that causes the hydrophobicproperties of the elastomers to take precedence.

The bioelastic polymers may include elastomeric units selected from thegroup consisting of bioelastic pentapeptides, tetrapeptides, andnonapeptides. By selecting the side changes present in the polymerportion of the composition, control is possible over the absorbenceproperties of the composition including the ability to the absorbent toretain absorbed liquid under stresses and external pressures. Properselection of hydrophobic (apolar) and polar residues, which is known byone skilled in the art, will provide the resulting polymer with theproperty such that it is soluble in water at low temperatures but as thetemperature is raised through a transitional range, they aggregate intocondensed, more-ordered states.

The above materials should be selected such that the temperature atwhich they form into a semi-solid material should be greater than thetemperature at which they do not have a semi-solid form. Desirably, thetemperature at which they form into a semi-solid material is from about35° to about 39° C., more desirably about 37° C. The temperature atwhich the material can be delivered to the vaginal canal is from about16° to about 27° C., desirably about 20° C.

With respect to each of the above materials, one skilled in the art canselect the appropriate material and/or modify the above material torender it more hydrophobic or more hydrophilic depending on the end useof the insert that is formed from the composition. For example, wherethe insert is to be used as an incontinence insert, the insert is formedfrom a composition that is non-absorbent and desirably hydrophobic. Onthe other hand, where the insert is to be used as a catamenial device,the insert is formed from a composition that is absorbent.

It is also contemplated that a withdrawal device 110 may be providedwith the composition such that upon delivery of the composition to thevaginal canal, the withdrawal device 110 may also be delivered to thevaginal canal so that as the composition solidifies, the withdrawaldevice 110 is secured within the insert formed as a result of thesolidification of the composition.

The composition including one of more of the materials described aboveis contained in a delivery device that will contain the compositionuntil delivery to the vaginal canal. The delivery device can include,but is not limited to an aerosol, squeeze tube, pump or otherapplicators (known in the art) to which a nozzle is attached or part ofthe container. Additionally a suppository, capsule, effervescent or foamproducing tablet or other suitable device to deliver the compositioninto the vaginal canal where upon introduction, the composition willsolidify to a semi-solid or solid form having elasticity and resiliency.

The present invention therefore contemplates a method of providing avaginal insert that includes providing a delivery device that contains acomposition and dispensing the composition to the vaginal canal wherethe composition is fluid like when outside the vagina but that uponcontact with the interior surface of the vaginal canal and rugae willsolidify to form a malleable, resilient insert suitable for use as anincontinence insert or catamenial insert depending upon the propertiesof the composition and independent of the location of the insert.

While the invention has been described in conjunction with specificembodiments it is to be understood that many alternatives,modifications, and variations will be apparent to those skilled in theart in light of the foregoing detailed description. It is thereforeintended that the foregoing description be regarded as illustrativerather than limiting, and that it be understood that it is the followingclaims, including all equivalents, that are intended to define thespirit and scope of this invention.

1. An anatomically conforming vaginal insert formed from a composition wherein the composition includes a material which is a semi-solid at a first temperature greater than a second temperature, which is about 20° C.
 2. The vaginal insert of claim 1 wherein the composition is selected from the group consisting of a material selected from polyurethane, silicone, a hydrogel, temperature sensitive polymeric materials, ion sensitive materials, bioelastic polypeptide polymers, a multi-component reverse thermo-sensitive polymeric system, and a fibrous absorbent structure resembling an open cell polymeric foam.
 3. The vaginal insert of claim 2 wherein the material is a temperature sensitive polymeric material having a low critical solution temperature such that the first temperature is about 37° C.
 4. The vaginal insert of claim 1 wherein the insert is hydrophobic.
 5. The vaginal insert of claim 4 wherein the vaginal insert is an incontinence insert.
 6. The vaginal insert of claim 5 wherein the vaginal insert supports musculature around a bladder neck.
 7. The vaginal insert of claim 1 wherein the insert is absorbent.
 8. The vaginal insert of claim 7 wherein the insert is a catamenial insert.
 9. The vaginal insert of claim 1 wherein the composition expands upon contact with the vaginal canal.
 10. The vaginal insert of claim 9 wherein upon expansion, the insert substantially fills an entire lateral portion of the vaginal canal. 